MI5 fears for the tradecraft of Thames House operatives if intercept evidence can be used in court. Photograph: Andy Rain/EPA

The government will attempt to make intercept evidence admissible in court, the Guardian has learned, in a move likely to bring ministers into conflict with the intelligence services.

Officials are already looking into reversing the ban, after both the Conservatives and the Liberal Democrats supported a change in the law while in opposition.

"The government supports the principle of using intercept as evidence in criminal proceedings," a Home Office spokesperson said. "This is a complex area and the government will now consider how to build on the work of the privy council committee to bring about a workable solution."

Senior intelligence and secret service officers have voiced continuing opposition to using the material in court. Top MI5 and MI6 officials have told the Guardian that the use of such evidence in court would reveal secret techniques and operations, and would prove too expensive by requiring officers to trawl through vast numbers of phone recordings.

"Abolishing the rule about intercept underpins the rhetoric of both the Conservatives and the Liberal Democrats about control orders and secret evidence," said Matthew Ryder QC, a barrister at Matrix chambers.

"What the government does now will be a serious indicator of whether their views on civil liberties are going to be different, or whether they will accede to security service interests in the same way that Labour did."

Almost all big criminal investigations in the UK involve the use of phone intercepts. But the Regulation of Investigatory Powers Act makes intercept evidence inadmissible in criminal cases, even if it could help to prove the innocence of the accused.

Evidence from bugs is already admissible and has been used in a number of terrorism trials, prompting arguments that the ban on intercept evidence is no longer sustainable.

Calls from lawyers and civil liberties groups to make intercept evidence admissible have led to eight reports in 14 years on the issue, including one by Sir John Chilcot, the senior civil servant who now heads the Iraq war inquiry. He concluded such evidence should be admissible but the consent of intelligence and law enforcement agencies should be obtained to protect secret techniques.

"It's not that simple," said Max Hill QC, from 18 Red Lion Court chambers, who has prosecuted in a number of terrorism trials. "Unless you have an investigation that has no reliance on intelligence sources – and let's face it most do – you are going to end up with transcripts of telephone evidence that is heavily redacted.

"It is difficult to see a way round the impact opening up intercept evidence would have on intelligence-gathering," Hill added. "It's going to be very difficult to achieve without real compromise by those who are enjoined to protect us."

Civil liberties groups said they intended to increase pressure on the government to resolve tension between the demands of the security services and the benefits of making intercept evidence admissible.

"The coalition parties have bound themselves together with statements on civil liberties. It will take early consistent action on repealing control orders and allowing the use of intercept evidence in fair criminal trials to keep those ties from fraying," said Shami Chakrabarti, director of human rights campaign Liberty.

"This evidence ought to be made admissible and the practical problems, which are real, will have to be confronted and solved, as they are in other countries," another senior criminal barrister said.